Todd Enterprises Homes For Rent, 2 Bedroom Houses In Jackson, Tennessee, Calvin Hill Power Of Publish, Scituate Ma Hockey Captain 2017, Articles C

In the case of Widening Type Casting, the lower data type (having smaller size) is converted into the higher data type (having larger size). with ids being an array of ints and touch being a pointer. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. A missing cast in the new fast > enumeration code. But I'm nitpicking .. Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin? This page has been accessed 1,655,678 times. A long long would not work for 32bit systems and a long would not work for 64 bit Windows (while 64bit Unix and Unix-like systems like OS X use the LP64 data model, in which a long is 64bit, 64bit Windows uses the LLP64 data model, in which a long has a size of 32bit (http://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_models)). Acidity of alcohols and basicity of amines. How to use Slater Type Orbitals as a basis functions in matrix method correctly? Pd = Pa; Similarly, Pc may be type cast to type int and assigned the value Pa. 1. even though the compiler doesn't know you only ever pass myFcn to pthread_create in conjunction with an integer. Casting a pointer to void* and back is valid use of reinterpret_cast<>. Press question mark to learn the rest of the keyboard shortcuts. As a result of the integer division 3/2 we get the value 1, which is of the int type. If we want to get the exact value of 7/5 then we need explicit casting from int to float: Example: int x=7, y=5; To perform a cast, specify the type that you are casting to in parentheses in front of the value or variable to be converted. If you are planning to use pthreads and you are planning to pass the pass function to pthread_create, you have to malloc/free the arguments you are planning to use (even if the threaded function just need a single int). Casting an open pointer to other pointer types and casting other pointer types to an open pointer does not result in a compile time error. If the function had the correct signature you would not need to cast it explicitly. No sense in writing a few dozen lines of extra code just to get a bunch of numbered threads. Bulk update symbol size units from mm to map units in rule-based symbology. returnPtr = (void **) malloc (x * sizeof(void *)); ptr = (void *) malloc (x * y * size); AC Op-amp integrator with DC Gain Control in LTspice. "because the type "int" supports only -32768 ~ 32768" This is not true for any modern desktop or mobile OS or any OS that is targeted by cocos2d-x. Whats the grammar of "For those whose stories they are"? See also this documentation.. From and Into are generally intended to be lossless, infalliable conversions.as on the other hand can discard data and lead to bugs in some situations, for example casting a u64 to a usize may truncate the value on a 32-bit host. ), For those who are interested. In the first example, the variable c1 of the char type is converted to a temporary variable of the int type, because the second operand in the division operation, the constant 2, is of the higher type int. On all of them int is 32bit, not 16bit. */void **MatrixIB (unsigned long x, unsigned long y, int size){ void *ptr; void **returnPtr; register unsigned long i, j; returnPtr = (void **) malloc (x * sizeof(void *)); ptr = (void *) malloc (x * y * size); for (i=0, j=0; j returnPtr[j] = (void *) (ptr + i); // <<< Compile Errors, Error1error C2036: 'void *' : unknown sizec:\temp\testone\lib\utils.c57, 2> returnPtr[j] = (void *) ((long*)ptr + i); // <<< No compile errors, 3> returnPtr[j] = (void *) ((char*)ptr + i); // <<< No compile errors. Fork 63. Just re-enforcing the old behavior of Xcode 5.0 and earlier versions, that already cut away parts of the address by casting it to int, won't introduce any new bugs and avoids the need to learn and understand lots of implementation-internal cocos code. rev2023.3.3.43278. this way you won't get any warning. */void **MatrixIB (unsigned long x, unsigned long y, int size){ void *ptr; void **returnPtr; register unsigned long i, j; Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Xcode 5 and iOS 7: Architecture and Valid architectures, xcode build error: Semantic issue cast from pointer to smaller type 'int' loses information, Issues in handling touches on subviews(uiviews) in UIScrollView, Architecture linking error after Xcode 5.1 upgrade, iOS 7.1 gives error after updating to Xcode 5.1, Linker error in Xcode 5.1 with cocos2d-x 3 beta 2. The difference between a and &a is the type. In this case, casting the pointer back to an integer is meaningless, because . Disconnect between goals and daily tasksIs it me, or the industry? casting from int to void* and back to int. Why is there a voltage on my HDMI and coaxial cables? @DavidHeffernan, sane thread APIs wouldn't send integral data to the thread procedures, they would send pointers. @DietrichEpp can you explain what is race condition with using. a cast of which the programmer should be aware of what (s)he is doing. How Intuit democratizes AI development across teams through reusability. Asking for help, clarification, or responding to other answers. Find centralized, trusted content and collaborate around the technologies you use most. The mapping in pointer<->integer casts is implementation defined, but the intent was that if the pointer type is large enough and isn't forcefully aligned (, But that's different. There is no "correct" way to store a 64-bit pointer in an 32-bit integer. If your standard library (even if it is not C99) happens to provide these types - use them. As with all cast expressions, the result is: Two objects a and b are pointer-interconvertible if: static_cast may also be used to disambiguate function overloads by performing a function-to-pointer conversion to specific type, as in. void* -> integer -> void* rather than integer -> void* -> integer. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. There's no proper way to cast this to int in general case. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. ", "!"? It's always a good practice to put your #define's in brackets to avoid such surprise. Why is this sentence from The Great Gatsby grammatical? Yesterday, I updated Xcode to the newest version (5.1 (5B130a)) to compatible with iOS 7.1. ^~~~~~~~~~~~~~~~~~~ /** Dynamically allocate a 2d (x*y) array of elements of size _size_ bytes. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. The preprocessor will replace your code by this: This is unlikely what you are trying to do. Converts between types using a combination of implicit and user-defined conversions. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Otherwise, if the original pointer value points to an object a, and there is an object b of the . Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Thanks. Where does this (supposedly) Gibson quote come from? cast to 'double *' from smaller integer type 'unsigned int' The C compiler is gcc, clang version 3.9.1, target aarch64--linux-android, thread model posix. Recovering from a blunder I made while emailing a professor. However the actual code in question contains an explicit c-style cast to int. Remarks. SQL Server does not automatically promote . Connect and share knowledge within a single location that is structured and easy to search. This explicit cast clearly tells the compiler "Shut up, I know that this code does not look correct, but I do know what I am doing". But I don't want to edit code in "EAGLView.mm" because it's a "library file". pthread create managing values generated in function (in c), Establishing TCP socket connection between PHP client and C server on Ubuntu. How to notate a grace note at the start of a bar with lilypond? Now, what happens when I run it with the thread sanitizer? If the original pointer value represents an address of a byte in memory that does not satisfy the alignment requirement of the target type, then the resulting pointer value is unspecified. You just need to suppress the warning, and this will do it: This may offend your sensibilities, but it's very short and has no race conditions (as you'd have if you used &i). Use returnPtr[j] = (void *) ((long)ptr + i); ). In a 64bit build a pointer is 64bit (contrary to a 32bit build, where it is 32bit), while an int is 32bit, so this assignment stores a 64bit value in a 32bit storage, which may result in a loss of information. pthread passes the argument as a void*. Terrible solution. However, I believe that even if the define was for the "65536", it would not be what @kaetzacoatl wanted. This is memory reinterpretation - a completely unacceptable way to do what the OP is trying to do. Get the address of a callback function to call dynamically in C++, error: call of overloaded function ambiguous, error: cast from to unsigned int loses precision [-fpermissive]. This is why you got Error 1 C2036, from your post. cast operators [edit] When an expression is used in the context where a value of a different type is expected, conversionmay occur: intn =1L;// expression 1L has type long, int is expectedn =2.1;// expression 2.1 has type double, int is expectedchar*p =malloc(10);// expression malloc(10) has type void*, char* is expected Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. what does it mean to convert int to void* or vice versa? ncdu: What's going on with this second size column? for (i=0, j=0; j should be the correct one. To cast such pointers to 32-bit types and vice versa special functions are used: void * Handle64ToHandle ( const void * POINTER_64 h ) void * POINTER_64 HandleToHandle64 ( const void *h ) long HandleToLong ( const void *h ) unsigned long HandleToUlong ( const void *h ) Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, You should be doing int x = *((int *)arg); You are casting from void * to int that is why you get the warning. BUT converting a pointer to void* and back again is well supported (everywhere). Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. If you are going to pass the address you typically need to exert some more control over the lifetime of the object. use $(ARCHS_STANDARD_32_BIT) at Architecture instead of $(ARCHS_STANDARD). SCAN_PUT_ATTR(key, ATTR, skey, FUNC); A nit: in your version, the cast to void * is unnecessary. I am compiling this program in linux gcc compiler.. then converted back to pointer to void, and the result will compare Please help me compile Chez Scheme. and how to print the thread id of 2d array argument? While working with Threads in C, I'm facing the warning, "warning: cast to pointer from integer of different size". However, you are also casting the result of this operation to (void*). linux c-pthreads: problem with local variables. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. B programing language is a language based on basic combined programming or a BCPL, and it is the precursor of the C programming language. Again, all of the answers above missed the point badly. LLNL's tutorial is bad and they should feel bad. } SCAN_END_SINGLE(ATTR) SCAN_PUT_ATTR(mask, ATTR, smask, FUNC); You are getting warnings due to casting a void* to a type of a different size. In such condition type conversion (type promotion) takes place to avoid loss of data. This is not even remotely "the correct answer". Taking the above declarations of A, D, ch of the . For example, the main thread could wait for all of the other threads to end before terminating. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. Note the difference between the type casting of a variable and type casting of a pointer. How to make compiler not show int to void pointer cast warnings, incompatible pointer types assigning to 'void (*)(void *)' from 'int (int *)'. So, when you cast a (void*) to (long), you are losing 32 bits of data in the conversion. But this code pass the normal variable .. Just edited. What you do here is undefined behavior, and undefined behavior of very practical sort. You need to cast the void* pointer to a char* pointer - and then dereference that char* pointer to give you the char that it points to! This is not a conversion at all. This is a fine way to pass integers to new pthreads, if that is what you need. However even though their types are different, the address is going to be the same. Bulk update symbol size units from mm to map units in rule-based symbology. How do I check if a string represents a number (float or int)? Offline ImPer Westermark over 11 years ago in reply to Andy Neil Except that you sometimes stores an integer in the pointer itself. If any, how can the original function works without errors if we just ignore the warning. Floating-point conversions For a fairly recent compiler (that supports C99) you should not store or represent address as plain int value. long guarantees a pointer size on Linux on any machine. Implementation-dependent. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Such pointers can be stored in 32-bit data types (for instance, int, DWORD). "I think what you should do is actually pass the address of the variable to the function" Not necessarily. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. I have a function with prototype void* myFcn(void* arg) which is used as the starting point for a pthread. 10) A prvalue of type pointer to void (possibly cv-qualified) can be converted to pointer to any object type. Pull requests. Mutually exclusive execution using std::atomic? But, sure, in that specific case you can pass a local variable address, type casting integer to void* [duplicate]. It was derived from the BCPL, and the name of the b language is possibly from the BCPL contraction. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. That's probably going to be true for most platforms you will ever encounter, but it's not a guarantee; it's implementation-dependent. In Java, there are two types of casting: Widening Casting (automatically) - converting a smaller type to a larger type size. An object pointer (including void*) or function pointer can be converted to an integer type using reinterpret_cast. Find centralized, trusted content and collaborate around the technologies you use most. *PATCH] platform/x86: hp-wmi: Fix cast to smaller integer type warning @ 2023-01-23 13:28 Hans de Goede 2023-01-23 13:56 ` Hans de Goede 0 siblings, 1 reply; 2+ messages in thread From: Hans de Goede @ 2023-01-23 13:28 UTC (permalink / raw) To: Mark Gross Cc: Hans de Goede, Andy Shevchenko, platform-driver-x86, kernel test robot Fix the following . C99 standard library provides intptr_t and uintptr_t typedefs, which are supposed to be used whenever the need to perform such a cast comes about. Put your define inside a bracket: #define M_TABLE_SIZE (64*1024) Now, you can do: static const void* M_OFFSET = (void*) M_TABLE_SIZE; without a problem. A pointer converted to an integer of sufficient size and back to the same pointer type is guaranteed to have its original value, otherwise the resulting pointer cannot be dereferenced safely ( the round-trip conversion in the opposite direction is not guaranteed [.]) This forum has migrated to Microsoft Q&A. p-util.c.obj "-c" ../lib/odp-util.c What is the difference between const int*, const int * const, and int const *? STR34-C. This is what the second warning is telling you. Why does setupterm terminate the program? Half your pointer will be garbage. The code ((void*)ptr + 1) does not work, because the compiler has no idea what size "void" is, and therefore doesn't know how many bytes to add. Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin?). Is it suspicious or odd to stand by the gate of a GA airport watching the planes? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. equal to the original pointer: First you are using a define, which is not a variable. The pointer doesn't actually point to anything, but it's the result of an earlier cast from an integer to a pointer (e.g. You are right! (int*)Pc = pa; After the execution of the above code all the three pointers, i.e., Pa, Pd, and Pc, point to the value 150. Apparently the clang version in Xcode 5.1 and above is more strict about potential 32bit vs. 64 bit incompatibilities in source code than older clang versions have been. Find centralized, trusted content and collaborate around the technologies you use most. Properly casting a `void*` to an integer in C++ 24,193 Solution 1 I think using intptr_t is the correct intermediate here, since it's guaranteed to be large enough to contain the integral value of the void*, and once I have an integer value I can then truncate it without causing the compiler to complain. Why is there a voltage on my HDMI and coaxial cables? All character types are to be converted to an integer. Instead of using a long cast, you should cast to size_t. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? I assumed that gcc makes a 65536 out of my define, but I was wrong. Don't pass your int as a void*, pass a int* to your int, so you can cast the void* to an int* and copy the dereferenced pointer to your int. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? How to convert a factor to integer\numeric without loss of information? GitHub Skip to content Product Solutions Open Source Pricing Sign in Sign up smadaminov / ovs-dpdk-meson-issues Public Notifications Fork 1 Star 1 Code Issues 66 Pull requests Actions Projects 1 Security Insights New issue I have looked around and can't seem to find any information on how to do this. There is absolutely not gurantee that sizeof(int) <= sizeof(void*). I wish that you write those answer first than the explanation. vegan) just to try it, does this inconvenience the caterers and staff? You need to pass an actual pointer. What is the point of Thrower's Bandolier?